阅读说明：本技术 一种改善led芯片外观的测试方法 (Test method for improving appearance of LED chip ) 是由 王克来 曹来志 白继锋 徐培强 张银桥 王向武 潘彬 于 2020-07-14 设计创作，主要内容包括：本发明公开了一种改善LED芯片外观的测试方法,该方法通过在电极透明导电膜上设置一个与4寸晶片形状大小一致的凸槽,将待测试的4寸晶片放置在测试机金属盘上,所述测试机金属盘上均匀分布着抽气孔,再将电极透明导电膜上的凸槽对应重叠覆盖在待测试的4寸晶片上,测试机上的抽气系统通过抽气孔抽气,使得晶片与电极透明导电膜紧密结合,测试完成后关掉测试机的抽气系统,即可轻易将电极透明导电膜移除,避免了撕去导电膜时造成晶片的破裂以及在晶片表面留下脏污；测试过程中,测试探针没有直接与P电极接触,极大的改善了芯片的外观。(The invention discloses a test method for improving the appearance of an LED chip, which comprises the steps of arranging a convex groove with the shape and the size consistent with that of a 4-inch wafer on an electrode transparent conductive film, placing the 4-inch wafer to be tested on a metal disc of a test machine, uniformly distributing air extraction holes on the metal disc of the test machine, correspondingly overlapping and covering the convex groove on the electrode transparent conductive film on the 4-inch wafer to be tested, exhausting air by an air extraction system on the test machine through the air extraction holes to enable the wafer to be tightly combined with the electrode transparent conductive film, turning off the air extraction system of the test machine after the test is finished, and easily removing the electrode transparent conductive film, so that the breakage of the wafer and the dirt left on the surface of the wafer when the conductive film is torn off are avoided; in the testing process, the testing probe is not directly contacted with the P electrode, so that the appearance of the chip is greatly improved.)

1. A test method for improving the appearance of an LED chip is characterized by comprising the following steps:

(1) manufacturing an electrode transparent conductive film, and arranging a convex groove with the shape and the size consistent with those of a 4-inch wafer on the electrode transparent conductive film;

(2) firstly, placing a 4-inch wafer to be tested on a metal disc of a testing machine, wherein air extraction holes are uniformly distributed on the metal disc of the testing machine, correspondingly overlapping and covering convex grooves on the electrode transparent conductive film on the 4-inch wafer to be tested, and exhausting air by an air exhaust system on the testing machine through the air extraction holes so that the wafer is tightly attached to the electrode transparent conductive film;

(3) in the air extraction process, the testing machine scans the 4-inch wafer to be tested, the P electrode of the core grain is identified through the electrode transparent conductive film, the testing probe is pricked to the electrode transparent conductive film to contact the P electrode, and the test is started;

(4) and after the test is finished, closing an air exhaust system of the tester, and removing the transparent conductive film of the electrode.

2. The test method of claim 1, wherein the test method comprises: the electrode transparent conductive film is composed of conductive particles and a resin adhesive, wherein the conductive particles are nickel-plated or gold-plated resin particles, the particle size of the conductive particles is 3-5 mu m, the resin adhesive is thermosetting resin, and the conductive particles on the motor transparent conductive film are mutually isolated.

3. The test method of claim 1, wherein the test method comprises: the electrode transparent conductive film comprises a base and convex grooves, the cross section of the base is square, the side length of the square is 150mm, the thickness of the base is 20-100 mu m, the light transmittance is larger than or equal to 70%, and the convex grooves with the same shape and size as that of a 4-inch wafer are arranged on the base.

4. The test method of claim 1, wherein the test method comprises: the diameter of the air exhaust hole is 100 mu m.

5. A test method for improving the appearance of LED chips according to claim 1 or 3, wherein: the height of the convex groove on the electrode transparent conductive film is 120-220 mu m.

6. The test method of claim 1, wherein the test method comprises: the electrode transparent conductive film can be repeatedly recycled.

7. The test method of claim 1, wherein the test method comprises: the 4-inch wafer is divided into a plurality of core particles, the lower ends of the core particles are fixedly connected into a whole, the upper ends of the core particles are not in contact with each other, and each core particle comprises a P electrode.

Technical Field

The invention relates to the field of semiconductor light emitting diodes, in particular to a test method for improving the appearance of an LED chip.

Background

The LED has the advantages of high luminous efficiency, low energy consumption, long service life, high environmental protection and the like, has become an indispensable photoelectric component in daily life, and is widely applied to the field of high-efficiency solid-state lighting, such as a digital tube, a display screen, a backlight source, an automobile lamp, a traffic signal lamp, landscape lighting and the like. After the production and processing of the LED chip are completed, the photoelectric parameters of the LED chip need to be tested. With the development of packaging technology, the size of an LED chip is smaller and smaller, and the market puts forward higher and stricter requirements on the appearance of the LED chip at the present stage, so that the requirements on a testing method are further improved. The P/N electrodes of the AlGaInP-based LED chip are usually on different surfaces, the P surface faces upwards in the test process, and a test probe is directly pricked on the P electrode. Because the test probe is relatively sharp, a probe mark can be left when the test probe is pricked on the P electrode, if the chip needs to be retested, a plurality of probe marks can appear, and the probe mark can become larger and larger along with the abrasion of the probe; in addition, when the operator works, the test probe is not aligned with the center of the electrode, and the phenomenon of needle mark deviation can occur. The appearance of the LED chip is seriously affected by overlarge and excessive pin marks and deviation, and the subsequent packaging process is adversely affected.

CN109755144A discloses a testing method for improving the appearance yield of GaN-based LED chips, in which an anisotropic conductive film is covered on a chip, and the two are bonded by heating, and the anisotropic conductive film is insulated in the X/Y direction and electrically conducted in the Z-axis direction, so that the non-contact measurement between a testing probe and a chip electrode is realized without aligning the conductive film with the chip electrode. In addition, in order to maintain the adhesive force of the anisotropic conductive film, it is necessary to store it at low temperature. After the test is finished, the anisotropic conductive film is adhered to the surface of the wafer, so that the wafer is easy to crack in the process of tearing off the anisotropic conductive film.

Disclosure of Invention

The present invention is directed to improving and innovating the disadvantages and problems of the related art and to providing a test method for improving the appearance of an LED chip.

In order to achieve the purpose, the invention provides the following technical scheme: a test method for improving the appearance of an LED chip comprises the following steps:

(1) Manufacturing an electrode transparent conductive film, and arranging a convex groove with the shape and the size consistent with those of a 4-inch wafer on the electrode transparent conductive film;

(2) firstly, placing a 4-inch wafer to be tested on a metal disc of a testing machine, wherein air extraction holes are uniformly distributed on the metal disc of the testing machine, correspondingly overlapping and covering convex grooves on the electrode transparent conductive film on the 4-inch wafer to be tested, and exhausting air by an air exhaust system on the testing machine through the air extraction holes so that the wafer is tightly attached to the electrode transparent conductive film;

(3) the testing machine scans a 4-inch wafer to be tested, a P electrode of a core grain is identified through the electrode transparent conductive film, a testing probe is pricked to the electrode transparent conductive film to contact the P electrode, and the test is started;

(4) and after the test is finished, closing an air exhaust system of the tester, and removing the transparent conductive film of the electrode.

In this embodiment: the transparent conductive film of the electrode consists of conductive particles and a resin adhesive, wherein the conductive particles are nickel-plated or gold-plated resin particles, the particle size is 3-5 mu m, and the resin adhesive is thermosetting resin.

In this embodiment: the electrode transparent conductive film comprises a base and convex grooves, the cross section of the base is square, the side length of the square is 150mm, the thickness of the base is 20-100 mu m, the light transmittance is larger than or equal to 70%, and the convex grooves with the same shape and size as that of a 4-inch wafer are arranged on the base.

In this embodiment: the diameter of the air exhaust hole is 100 mu m.

In this embodiment: the height of the convex groove on the electrode transparent conductive film is 120-220 mu m.

In this embodiment: the transparent conductive film of the motor can be repeatedly recycled.

In this embodiment: the 4-inch wafer is divided into a plurality of core particles, the lower ends of the core particles are fixedly connected into a whole, the upper ends of the core particles are not in contact with each other, and each core particle comprises a P electrode.

In summary, due to the adoption of the technical scheme, the invention has the beneficial effects that:

(1) the invention covers 4 inches of chip correspondingly in the convex groove of the transparent conducting film of the electrode while testing, carry on the air exhaust to chip and transparent conducting film of the electrode through the air exhaust system of the tester, rely on the atmospheric pressure to make chip to be measured and transparent conducting film of the electrode closely laminate, then discern the P electrode of the core grain through the transparent conducting film of the electrode, prick the probe to the transparent conducting film of the electrode and contact the P electrode, test, turn off the air exhaust system of the tester after the test is finished, can remove the transparent conducting film of the electrode easily, has prevented from tearing the breakage of the chip and leaving the smudgy on the surface of the chip when tearing off the conducting film;

(2) in the test process, the test probe is not directly contacted with the P electrode, so that the appearance of the chip is greatly improved;

(3) Because the conducting film is not bonded with the wafer through an adhesive, compared with other methods, the method has the advantages that the operation is simpler and more convenient, the electrode transparent conducting film can be repeatedly used, and the test cost is reduced.

(4) The conductive particles on the transparent conductive film of the electrode are mutually isolated, the transparent conductive film of the motor is pressed by the test probe, so that the longitudinal conductive particles are contacted, the transparent conductive film of the electrode is longitudinally conducted and transversely non-conductive, the transparent conductive film of the electrode is not interfered by other core particles in the test process, the distance between the electrodes of the core particles is not influenced in the test process, and the 4-inch wafer is cut into the core particles with any size.

Drawings

FIG. 1 is a schematic view of a transparent conductive film with a convex groove for an electrode;

FIG. 2 is a schematic top view of a 4-inch wafer to be tested after being covered with a transparent conductive film for an electrode;

FIG. 3 is a schematic rear view of a 4-inch wafer to be tested covered with a transparent conductive film for electrodes;

FIG. 4 shows the appearance of the chip P motor after the test of the present invention is completed;

FIG. 5 shows the appearance of a chip P motor after the test is completed by a conventional method;

reference numerals: metal discs 1, 4-inch wafers 2 of a tester, P electrodes 3 of core particles, test probes 4, transparent conductive films 5 of electrodes, air extraction holes 6, core particles 7 and convex grooves 51.

Detailed Description

The embodiments will be described in detail with reference to fig. 1 to 5.

The invention provides a test method for improving the appearance of an LED chip, which comprises the following steps:

(1) manufacturing an electrode transparent conductive film 5, wherein the electrode transparent conductive film 5 is shown in figure 1 and comprises conductive particles and a resin adhesive, the conductive particles are nickel-plated or gold-plated resin particles, the particle size is 3-5 micrometers, the resin adhesive is thermosetting resin, the thickness of the electrode transparent conductive film 5 is 20-100 micrometers, the light transmittance is larger than or equal to 70%, the conductive particles on the electrode transparent conductive film 5 are mutually isolated, the electrode transparent conductive film 5 comprises a base 52 and convex grooves 51, the cross section of the base 52 is a square with the side length of 150 mm, the thickness of the base 52 is 20-100 micrometers, and the convex grooves 51 with the shape and the size consistent with that of a 4-inch wafer 2 are arranged on the base 52;

(2) as shown in fig. 2, a 4-inch wafer 2 to be tested is placed on a metal plate 1 of a testing machine, air extraction holes 6 with the diameter of 100 μm are uniformly distributed on the metal plate 1 of the testing machine, a transparent conductive film 5 of an electrode is correspondingly overlapped and covered on the 4-inch wafer 2 to be tested, an air extraction system of the testing machine is started, the air extraction system extracts air through the air extraction holes 6, the 4-inch wafer 2 is tightly attached to the transparent conductive film 5 of the electrode by virtue of atmospheric pressure, the 4-inch wafer 2 is divided into a plurality of core grains 7, the lower ends of the core grains 7 are fixedly connected into a whole, the upper ends of the core grains 7 are not contacted with each other, and each core grain 7 comprises;

(3) The testing machine scans a 4-inch wafer 2 to be tested, a P electrode 3 of a core grain is identified through an electrode transparent conductive film 5, a testing probe 4 is pricked on the electrode transparent conductive film 5 to contact the P electrode for testing, conductive particles on the electrode transparent conductive film 5 are isolated from each other, and after the motor transparent conductive film 5 is pressed by the testing probe 4, the longitudinal conductive particles are contacted, so that the electrode transparent conductive film is longitudinally conducted and transversely conducted, and the testing process is not interfered by other core grains 7;

(4) after the core grains 7 on the 4-inch wafer 2 are tested, the air suction system of the testing machine is closed, the electrode transparent conductive film 5 is removed, the wafer continues to flow for the next process, and the problem of adhesive failure does not exist because the wafer does not need to be contacted by an adhesive, so that the electrode transparent conductive film 5 can be repeatedly used. The electrode surface of the chip after the test is completed has no pin mark, as shown in fig. 4.

Comparative example: testing chips using conventional methods

The chip for testing is the same as the present embodiment, and the chip is tested by the conventional method, and the testing probe is directly stuck on the P electrode of the chip, as a result, as shown in fig. 5, an excessive pin mark is left on the P electrode of the chip.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.